/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesCommon/Public/Online/SessionsCommon.h
virtual [TOptional](API\Runtime\Core\IO\TOptional)< [FOnlineError](API\Plugins\OnlineServicesInterface\Online\FOnlineError) > CheckState ( const [FJoinSession::Params](API\Plugins\OnlineServicesInterface\Online\FJoinSession\Params) & Params ) const